3B2 SCSI Soft Power fun...

[Greg A. Woods]

I just went through an episode that gave me a good scare.

I came home this evening to find my DM/135e with its power light out
and tons of messages spewing out on the console about a bad block 0 on
that device.  Oh-oh!  I tried an emergency power down, but it
"failed", so I logged in and tried 'telinit 0' which eventually worked.

When I tried to power back up, only the DCM/4e came on, and not even
the TM/60S!  After much goofing around and searching through the
maintenance manual, I finally looked at the SCSI Operations Manual.
A very short paragraph suggested shutting everything off *and*
disconnecting all of the power cables, and starting up from scratch.

It almost worked, but I was getting funny clicks from my new line
conditioner (TrippLite LS-600 b).  I also noticed noise on my AM radio
when I removed the power cords from units that were supposedly off.

Ah yes!  That wee paragraph said problems might occur if either
someone accidentally powered off a module, *or* if there were
un-expected power transients.

So, I removed the "line conditioner" from the power bar and went
through the disconnect procedure again before everything was stable.

I think I'll leave the line conditioner for some other application,
after I check it's output under load with a scope!  Meanwhile, I think
that I'll let those "intelligent" SCSI module power supplies fend for
themselves.
-- 
						Greg A. Woods

woods@{robohack,gate,eci386,tmsoft,ontmoh}.UUCP
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